A differential pressure type flow rate measuring device or a differential pressure type flow rate control device uses a fluid resistance device for producing a differential pressure. Example fluid resistance devices include an orifice member formed by opening a fine pore on a plate material and a capillary member formed by a metal fine canal.
Meanwhile, whether the orifice member is used or the capillary member is used is selected appropriately depending on a flow rate or a viscosity of a fluid. When focusing attention on the capillary member, as shown in FIG. 1 and FIG. 2 in the patent document 1, conventionally the capillary member is so configured that a metal fine canal is connected by being welded to a fluid flow channel formed in a block body or the like.